Surface Molecular Composition and Electrical Property of Cationic Solid Lipid Nanoparticles with Assembled Lipid Layer Mediated by Noncovalent Interactions

Understanding of charged groups on nanostructured lipid particles is an important issue in nanomedicine development. This study presents the relation between noncovalent interactions and the composition of ionogenic groups in the assembled lipid layer of cationic solid lipid nanoparticles (CSLNs). Innovated CSLNs containing cacao butter, cholesterol, stearylamine, and esterquat 1 (EQ 1) were fabricated by modified solvent diffusion method. The results revealed that the average diameter of CSLNs decreased when the weight percentage of cholesterol and EQ 1 increased. X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy evidenced strong interactions between cholesterol and EQ 1. These noncovalent interactions exhibited hydrophobic and cation–aromatic characteristics and mediated the distribution of lipids in the external layer of CSLNs. In addition, an increase in the weight percentage of cholesterol and EQ 1 enhanced the zeta potential, electrophoretic mobility, and fixed charge dens...